Purpose: We report the case of a patient with stromal herpetic keratitis and the onset of nontuberculous mycobacterial infection during treatment.
Patient: The patient was a 69-year-old female who had been treated with steroid eye drops for 7 years due to stromal herpetic keratitis in the left eye. As the onset of hypopyon was observed, she was referred to our department. At the initial visit, right corrected visual acuity was 1.0, left visual acuity was 10 cm CF, and multiple irregular corneal abscesses with hypopyon, ciliary hyperemia, and corneal epithelial defects were observed in the left eye. Microscopic examination of the corneal scrapings revealed no bacteria or fungi. Treatment for suspected necrotizing herpetic keratitis, levofloxacin and betamethasone eye drops and oral valacyclovir were started; however, the inflammation persisted. Keratomycosis was suspected, and antifungal eye drops were added to the regimen, but little improvement was observed. Corneal thinning gradually progressed, leading to corneal perforation. Therefore, therapeutic keratoplasty was performed. Ziehl-Neelsen staining of the excised corneal specimens revealed nontuberculous mycobacteria in the deep stroma. Gatifloxacin and tobramycin were instilled postoperatively. One year and four months after the surgery, no recurrence of infection was observed, and the patient's left corrected visual acuity was 0.2. Polymerase chain reaction (PCR) was performed on excised corneal tissue sections, and Mycobacterium chelonae was identified as the putative causative bacterium.
Conclusions: The patient underwent penetrating keratoplasty for drug-refractory stromal herpetic keratitis and was pathologically diagnosed with nontuberculous mycobacterial keratitis. Corneal scrapings were taken multiple times, but acid-fast staining was not performed. In patients with refractory keratitis previously treated with topical steroids, the possibility of infection with non-tuberculous mycobacteria as the causative bacteria must be considered. Additionally, PCR testing of histopathologic specimens is a useful aid for diagnosis.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 125: 136-141, 2021.